Optical disks such as DVDs or CDs are popular for storing and playing entertainment selections including movies, songs and other video and audio performances, as well as reading and writing computer programs and data. Single disk drives and disk changers or multi-play changers abound in consumer and commercial applications.
Early optical disks were often permanently enclosed in cartridges, affording protection of the optical media surface. Early optical disk changers handled multiple cartridges, expanding the amount of data accessible in a given device. Access by a read or read/write head in such a changer was made through a slot in the optical media cartridge. The optical disk was generally not removable from the cartridge.
More recently, optical disks in the form of DVDs or CDs have largely replaced the older optical disks in cartridges. DVD changers and CD changers usually have these disks on a rotatable platter carousel, in a toroidal carousel or stacked in a magazine, although there may be other types of disk changers. Handling the bare disks while loading them in and out of these types of changers exposes the disks to fingerprints, scratching and other types of damage, since the disks are not in a cartridge.
When bare disks are removed from a changer to be put back on a shelf or elsewhere in storage, the user must handle the bare disk and place it back in a storage case, either one in which the disk was originally sold or a replacement case, for example as might occur in a rental store. The process is reversed every time a disk is selected from a shelf for storage and placed into the changer or the magazine for the changer, exposing the disk to damage with each direction and repetition.
Frequent handling of bare disks, and associated damage to them, might also occur in the operation of a movies-on-demand business, where video streams of movies are sent from a server by request to customer Internet addresses. A selection of popular movies is available from a DVD changer at the business location. A worker at that location manually selects a movie from shelves or other long-term storage when a less popular movie is requested by a customer, inserting the disk into the changer to play, and removing it from the changer when done, to return the movie to its shelf or other storage. Periodically, as a movie wanes in popularity, it is removed from the changer and put into storage. Each removal of the disk from its case in order to place it as a bare disk into the changer, and each removal of a bare disk from a changer to put it back into its case for storage risks damage to the disk.
A software-on-demand business, a remote data access and archiving business, an engineering operation such as a design center or scientific operation requiring handling of multiple, large databases with both frequent access and archiving needs might have a similar system. Human workers or robotics, such as a robot arm, could move disks to and from a changer and long-term storage.
Considerable time overhead and cumulative disk damage results from numerous repetitions of removing bare disks from long-term storage cases, moving them and inserting them into a disk changer, removing them from a disk changer, moving them and putting them back into long-term storage cases.
If the disks could remain in cartridges during shelving or other storage, they would be as well protected as in their original cases. If these disks within cartridges could be used in a disk reader or read/write unit, without the need of removing the disk from its storage case and putting it as a bare disk into a reader, read/write unit, changer or magazine for a changer, there would be a savings of time for the user as well as a decreased likelihood of damage of the disk. In combining the protective advantages of a disk within a cartridge and the replaceability of a bare disk that is removable from a cartridge and not permanently encased within it, problems arise as to how to have the disk removable from the cartridge by the user and how to access the disk for reading or writing when the cartridge containing the removable disk is placed in a system.
U.S. Pat. No. 5,917,803, to Goto et al., discloses a disk cartridge adapted for permitting the removal of a disk. The disk cartridge has a case with a disk slot at one end for receiving a disk such as a CD-ROM or other optical disk. An opening is provided so that the disk motor and pickup can be inserted into the disk case in order to rotate and drive the disk. There is a shutter with a shielding plate for opening and closing the opening. The disk remains entirely within the case while the disk motor and pick up rotate and drive the disk. A lid rotates to open and close a disk access for insertion and removal of the disk through the disk slot, as could be done by a user when the cartridge is not within the drive.